An estimated crowd of up to 700 people filled Garema Place in stifling heat on Friday afternoon, waving placards as they called for Mr Morrison to be "sacked".

The crowd was a mix of young and old, of students and workers, brought together by a common concern and simmering sense of frustration.

Some wore P2 masks, an accessory made necessary by the hazardous bushfire smoke which has blanketed Canberra in recent weeks - albeit not on Friday. One protester wept. Some stood silently. Many screamed and chanted.

A young girl nervously moved to the front of the crowd to display a sign which read: 'How can I be a vet if all the animals are gone?'.

The so-called #SackScoMo rally was organised by Uni Students for Climate Justice. Similar rallies were held across the country on Friday, with large crowds gathering in Sydney, Melbourne and Brisbane.

Mr Morrison has faced heavy criticism for his handling of the bushfire crisis, starting with his decision to holiday in Hawaii while large swathes of NSW were engulfed in flames.

The prime minister has dramatically escalated the federal government's response to the national emergency in recent weeks, headlined by a $2 billion commitment to a bushfire recovery fund.

But for those gathered at Garema Place, the government's response amounts to too little, too late.

"I think our political leaders have been more interested in supporting their interests than thinking about the future," said Carol Green, who was carrying a sign which read "Nanas for a green future'.

A shared feeling of helplessness about the unfolding crisis drew university students Imogen Craig, Shweta Venkataraman and Sydney Oakman to Friday's rally.

"The bushfires have magnified those feelings," Shweta said.

"It can be frustrating knowing that we are desperately trying to individually change our own actions, on a bigger scale it's not much if the government isn't reflecting that."

Asked what message they wished to send to Mr Morrison and other political leaders, Sydney was blunt.

"Think for the long term, not for the short term," she said.

United Firefighters Union ACT branch secretary and national president Greg McConville led the rally in a moment's silence in honour all who have died during the bushfire crisis. The crowd then broke out in loud applause, a tribute to the paid and volunteer fire crews still out on the frontline.

"There are two things about firefighters and firefighting that need to be said," Mr McConville told the crowd.

"The first is that our members have a philosophy of leaving the job in better shape than they found it. The second is that on their worst day, firefighters still give 100 per cent effort, because if they don't then people will die.

"Our politicians would do well to match the effort and commitment of firefighters in addressing the very real escalation of fire risks and the very real pain and loss that communities now face."

The Melbourne rally went ahead on Friday despite Premier Daniel Andrews and Victoria Police calling for it to be postponed.

Mr Andrews warned organisers that they risked losing support for their cause by staging an event which diverted police resources during the bushfire crisis.

Speaking ahead of Friday's rally in Garema Place, Chief Police Officer Ray Johnson was confident the event would not put an extra burden on police. A small number of officers were present at the event, which The Canberra Times attended.

Chief Minister Andrew Barr was not concerned about the event, although he did question one aspect about its timing.

"5 o'clock in Garema Place on a hot Friday afternoon ... it's not the time I'd pick for such an event," he said.